| Full text | |
| Author(s): |
Ferreira, Rafael A.
;
dos Santos, Maria Elenice
;
Morilla-Santos, Cassio
;
Lebullenger, Ronan
;
Pena, Octavio
;
Lisboa-Filho, Paulo Noronha
Total Authors: 6
|
| Document type: | Journal article |
| Source: | CERAMICS INTERNATIONAL; v. 40, n. 8, p. 6-pg., 2014-09-01. |
| Abstract | |
Polycrystalline oxide materials with nominal compositions BiMn2O5 and Bi0.9Eu0.1Mn2O5 were obtained by urea combustion. Crystallographic studies using X-ray diffraction and Rietveld Refinement techniques showed the formation of single-phase samples for both compositions, crystallizing in a mullite-type orthorhombic perovskite structure, space group Pbam (Z=4). Replacement of Bi+3 by Eu+3 promoted a slight distortion and a unit cell contraction due to a decrease of the c-parameter for Bi0.9Eu0.1Mn2O5. The SEM/EDX techniques confirmed the formation of single-phase materials with excellent mapping distribution. Magnetic measurements showed different behaviors: BiMn2O5 is an antiferromagnet (AFM) with a Neel temperature (T-N) of 41 K and a Curie-Weiss temperature Theta(CW) of -277 K, while Bi0.9Eu0.1Mn2O5 displayed a ferrimagnetic behavior with a T-C of 44K and Theta(CW) of 270 K. The role of Eu+3 and the mechanisms responsible for the magnetic transition are discussed on the basis of chemical bonds and exchange interactions. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved. (AU) | |
| FAPESP's process: | 07/08072-0 - Fundamental research in superconductivity and magnetism - systems potentially useful for aplications: advanced oxides and superconductors patterned with artificial structures |
| Grantee: | Wilson Aires Ortiz |
| Support Opportunities: | Research Projects - Thematic Grants |
| FAPESP's process: | 13/07296-2 - CDMF - Center for the Development of Functional Materials |
| Grantee: | Elson Longo da Silva |
| Support Opportunities: | Research Grants - Research, Innovation and Dissemination Centers - RIDC |